Dry Cow Therapy & Management 干奶牛护理和管理 Erin Royster, DVM, MS University of Minnesota China Dairy Conference Hohhot, China October 26-28, 2015 艾琳 罗伊斯特博士美国明尼苏达大学中国奶牛大会
Outline 概要 Significance of dry cow mastitis 干奶牛乳腺炎的重要性 Risk factors 风险因素 Strategies to prevent new infections during the dry period 干奶期防止新发感染策略
Significance 重要性 The dry period is a significant period of risk for new infection 干奶期是新感染风险显著期 50-60% of all new infections caused by environmental pathogens occur during the dry period (Bradley & Green, 2000) 50%-60% 由于环境病原引起的新感染发生在于干奶期 ( 布拉德利和格林,2000 年 ) Over 50% of clinical coliform mastitis events in the first 100 days in milk originated during the dry period. (Bradley and Green, 2002) 超过 50% 的在泌乳 100 天发生的临床大肠杆菌乳腺炎案例起源于干奶期 ( 布拉德利和格林,2002 年 )
从泌乳期增加的感染每100 头奶牛案例数Significance 重要性 从干奶期增加的感染 泌乳月数 Origin of Infection (dry period or lactation) in cases of clinical mastitis (Green et al., 2002) 临床乳腺炎感染病例的感染来源 ( 干奶期或哺乳期 ) ( 格林等人,2002)
Significance 重要性 Proportion of quarters developing a new infection during the dry period: 干奶期乳房新感染比例 8-12% of quarters (Eberhart, 1986) 17% of quarters (Dingwell et al., 2001) 25% of quarters (Godden et al., 2003) 6-26% of quarters (Cook et al., 2004) Large variation among herds 牛群中变异较大 An opportunity area for a majority of dairy herds. 一个对大多数奶牛群有机会的领域
RISK FACTORS 风险因素
Why do dry cows get mastitis? 为什么干奶牛会得乳腺炎? The dry or involuted mammary gland has some resistance to new infection 干 或复原的乳腺对新感染有一些抵制力 But, new infection still occurs often 但是新感染仍经常会发生
Mammary Gland Defenses 乳腺防御 Lactoferrin 乳铁蛋白 Increased concentration 增加浓度 Inhibits bacterial growth by binding iron 通过结合铁抑制细菌生长 Increased leukocyte activity 增加白细胞活性 Increased concentration 浓度增加 Increased function (less interference from milk fat and casein) 增强功能 ( 较少来自乳脂肪和酪蛋白的干扰 ) Keratin plug formation 角质栓的形成 Physical barrier 物理屏障 Fatty acids inhibit bacterial growth 脂肪酸抑制细菌生长
High Risk Periods for New Infections 新发感染高风险期 新感染率 1. Just after dry-off involution 在干奶期后 - 退化 1. Just before calving colostrogenesis 在产犊前 初乳开始 干奶期 哺乳期
High Risk Periods for New Infections 新发感染高风险期 Involution 退化 No flushing action 无冲洗 Delayed keratin plug formation 延迟角质栓的形成 Lactoferrin diluted 乳铁蛋白稀释 Inhibited leukocyte function 抑制白细胞功能 Colostrogenesis 初乳形成 Protective factors diluted 保护性因素稀释 Immune suppression 免疫抑制 Keratin plug may break down 角质栓可能破裂 Antibiotic dry cow therapy (DCT) levels below the minimum inhibitory concentration (MIC) 抗生素干牛治疗 (DCT) 低于最小抑制浓度水平 (MIC)
Herd: 牛群 Risk Factors 风险因素 Bulk tank somatic cell count (SCC) 散装罐体细胞数 Prevalence of infection 感染率 Herd management practices (sanitation, heat abatement, crowding, other stressors, bedding management) 牛群管理实践 ( 卫生, 热消除, 拥挤, 其他应激因子, 卧床管理 )
Risk Factors 风险因素 Cow: 牛 Lactation number: older cows at risk 泌乳数量 : 较老的奶牛有风险 High milk yield at dry off 干奶期高奶产量 Method of drying cows off 使牛干奶的方法
Risk Factors 风险因素 Quarter: 乳房 Teat end exposure to bacteria 乳头端接触细菌 Teat end condition 乳头端状况 Timely formation of keratin plug 角质栓及时形成
Teat End Condition 乳头端状况 Hyperkeratosis predisposes teats to bacterial colonization. (Fox, 1997; Timms, 1998) 角化过度使得奶头易细菌定植 Cracked teats are at 1.8 times higher risk for acquiring new infections during dry period. (Dingwell et al., 2004) 破裂的乳头在干奶期感染风险高达 1.8 倍 Hyperkeratosis no crack 角化过度 - 无裂纹 Hyperkeratosis cracked 角化过度 - 裂纹
Keratin Plug in the Teat Streak Canal 角质塞在乳头条纹渠道 Keratin plug formation important to prevent infection 角质栓的形成对防止感染很重要 (Dingwell et al., Prev. Vet. Med, 2004)
Proportion of Quarters Failing to Produce an Adequate Keratin Plug During the Dry Period 干奶期未能提供足够的角质栓的乳头比例 新西兰牛低产美国牛 高产美国牛 干奶期后的天数 Bradley & Green
PREVENTION STRATEGIES 预防策略
Prevention Strategies 预防策略 Antibiotic Dry Cow Therapy (DCT) 抗生素干奶牛疗法 Teat Sealant 乳头密封胶 Drying off methods 干奶方法 Dry cow management environment, nutrition, vaccination 干奶牛管理 - 环境, 营养, 免疫接种
Antibiotic Dry Cow Therapy 抗生素干奶牛疗法 Intramammary infusion with long-acting antibiotic at dry off 在干奶期乳房内注射长效抗生素 Widely adopted, 73% of US dairy operations use blanket approach (NAHMS, 2008) 广泛采用,73% 的美国牧场使用覆盖方法 Purpose: 目的 Cure existing subclinical infections 治愈现有的亚临床感染 Some clinical infections will have best chance of cure over the dry period 干奶期一些临床感染有治愈的最佳机会 Prevent new infections during the dry period 干奶期预防新感染 (Smith, 1966; Browning, 1990; Bradley and Green, 2001; Bradley and Green, 2004)
Antibiotic Dry Cow Therapy 抗生素干奶牛疗法 Limitations: 局限性 Will not prevent infections caused by resistant bacteria 无法防止因抗药性细菌引发的感染 Will not prevent infections in late dry period 无法在干奶期后期预防感染 May not be necessary to treat uninfected cows with antibiotics 没有必要对未感染的牛用抗生素
Dry Cow Teat Sealants 干奶牛乳头密封胶 Internal teat sealants 乳头内封胶 Orbeseal or TeatSeal (Zoetis) External teat sealants 乳头外封胶 e.g. T-Hexx Dry (Hyrdromer, Inc.)
External Teat Sealants 乳头外封胶 Rapid drying plastic polymer 速干塑料聚合物 Forms a physical barrier to entry by bacteria 形成一个物理屏障防止细菌进入 T-Hexx Dry. (Hydromer, Inc.) Stronghold / DryFlex (WestAgro, DeLaval off the market)
External Teat Sealants 乳头外封胶 Advantages: 优点 Easy to apply 易于应用 Rapid drying 快速干燥 Non-irritating / non-toxic 无刺激性 / 无毒 Stronghold - Day 4 Disadvantage: 缺点 Shed off teat in 3-7 days 3-7 天从乳头脱落 For full benefit must apply at dry off, and then reapply at 10 days pre-calving, then repeat as needed until calving. 为了充分发挥效用, 必须在干奶期后使用, 产犊前十天再次使用, 然后根据需要重复使用直到产犊
Internal Sealants 乳头内封胶 Orbeseal / TeatSeal (Zoetis) 硕腾 Bismuth subnitrate in a paraffin base 石蜡为基质的次硝酸铋 Infused into quarter after last milking at dry-off 在干奶期最后一次挤奶后注入乳房 Insoluble in milk excellent persistence 不溶于牛奶 优良的持久性
Post-Calving 产后 Orbeseal is easily hand-stripped out of the quarter after calving (if infused properly). Orbeseal 很容易在产犊后用手剥离出乳房 ( 如果注入正确 ) Safely ingested by calf. 牛犊安全摄入 No antimicrobial properties or residue issues. 无抗菌性或残留问题 May cause residues in equipment problem for cheese production. 可能导致设备里的残留 - 奶酪生产的问题
Summary of Findings from Selected Internal Teat Sealant Studies 所选内部乳头密封胶研究结果小结 In uninfected cows: 对未感染的牛 Use of Orbeseal alone results in fewer new infections compared to no treatment 相比无治疗, 单独使用 Orbeseal 导致更少的新增感染 Use of Orbeseal is at least equal if not better at preventing infections than antibiotic DCT alone. 就算没有效果更好, 使用 Orbeseal 至少跟用抗生素 DCT 效用是一样的 References: 参考文献 Berry and Hillerton, JDSci 2002 Huxley et al., 2001
Summary of Findings from Selected Internal Teat Sealant Studies 所选内部乳头密封胶研究结果小结 In cows of unknown infection status or infected cows 未知感染状况或感染的奶牛 Orbeseal plus antibiotic DCT resulted in a significant reduction in new infections compared to using antibiotic DCT alone: 相比单独使用抗生素 DCT,Orbeseal 加抗生素 DCT 能显著减少新感染 30 68% decrease in new infection risk during dry period 干奶期减少 30 68% 新发感染风险 20 30% decrease in clinical mastitis risk in early lactation 早期泌乳期临床乳腺炎降低 20 30% 风险 Decreased somatic cell count after calving 产犊后体细胞数降低 References: 参考文献 Godden et al., 2003; Cook et al., 2004
Summary of Findings from Selected Internal Teat Sealant Studies 所选内部乳头密封胶研究结果小结 Cost effectiveness of using antibiotic and teat seal in combination may vary by herd. 使用抗生素和乳头密封组合的成本效益在不同牛群中可能不同 Must use clean infusion techniques. 一定要用干净的注入技术
Dry Period Management 干奶期管理 Factors to consider: 要考虑的因素 Prevalence of cows with high SCC at dry off 在干奶期奶牛患病率伴随着高体细胞计数 Prevalence of new infections in first 100 DIM 产后平均第一个 100 天新发感染率 Length of dry period & consistency 干奶期长度和一致性 Production level at dry-off 干奶期生产水平
Is there a best method for drying off cows? 干奶牛的最佳方法是什么? High milk yield at dry off is associated with delayed teat closure and higher risk for new infections during the dry period (Huxley et al., 2002) 干奶期高牛奶产量是由于奶头延迟关闭和干奶期较高的新发感染风险
Is there a best method for drying off cows? 干奶牛的最佳方法是什么? We can reduce milk yield at dry-off and reduce infection risk by: 我们可以减少干奶结束期产奶量, 降低感染的风险, 通过 : Intermittent milking (once per day) for last 2 weeks of lactation, compared to abrupt cessation of milking (Oliver, J. et al., 1956) 不是突然停止挤奶, 在泌乳期最后两周间歇挤奶 ( 每天一次 ) Decrease energy ration density (Oliver, S. et al., 1990) 降低能量比密度 Each dairy should evaluate whether this is necessary 每个牧场应该评估这是否必要
Does Dry Period Length Affect Mastitis Risk? 干奶期长短影响患乳腺炎风险吗? Conventional practice: 40 to 60 day dry period 常规 : 干奶期 40 到 60 天 Dry period 60 days increases risk for infections (Rindsig et al., 1978) 干奶期 60 天会增加感染风险 Dry period <30 days might impact production and risk for mastitis mixed results from studies 干奶期 <30 天可能会影响产量和乳腺炎风险 - 研究的结果不一
Dry Cow Environment 干奶牛环境 Goal: minimize pathogen exposure to the teat end 目标 : 最大限度地减少病原体接触到奶头端 Bacteria need moisture and organic material (soil, manure, organic bedding) to survive 细菌需要水分和有机物质 ( 土壤, 肥料, 有机草垫 ) 生存 Keep it clean and dry 保持清洁和干燥 Bedding selection & maintenance 草垫选择和维护 Manure management 肥料管理 Ventilation 通风
Maximizing the Cow s Immune Defenses 最大限度地提高奶牛免疫防御 Nutritional management during dry and transition periods: 干奶和围产期的营养管理 : Dietary protein and energy 饮食中蛋白质和能量 Vitamins: A,D and E 维生素 A,D 和 E Minerals: Selenium, Copper, Zinc, etc.. 矿物质 : 硒, 铜, 锌等 Don t restrict feed and water intake: palatable and available 不限制饲料和水的摄入 : 适口和充足
Maximizing the Cow s Immune Defenses 最大限度地提高奶牛免疫防御 Minimize stressors: 最小的应急因素 : Good cow comfort 舒适度 Excellent ventilation 良好的通风 Prevent overcrowding 避免过度拥挤 Provide heat abatement (shade, fans, sprinklers) 提供热量减排 ( 遮阴, 风扇, 洒水器 )
Vaccination & Immunity 接种疫苗和免疫 Vaccination with Gram-negative core antigen allows the immune system to more rapidly and effectively respond to natural infections: 接种革兰氏阴性核心抗原使免疫系统更迅速和有效地对应对自然感染 Does not prevent coliform infections 不能防止大肠杆菌感染 Reduces duration and severity of coliform mastitis 减少大肠菌乳腺炎持续时间和严重程度 Reduces death loss 减少死亡损失 (Cullor, 1991; Hogan, 1992, 1999)
Vaccination & Immunity 接种疫苗和免疫 Routine vaccination beneficial and costeffective in almost all herds 几乎对所有牛群常规接种非常有益而且具有成本效益 (DeGraves and Fetrow, 1991) Will not overcome poor management 无法取代管理不善
Summary 总结 The dry period is a high risk period for new IMI 干奶期是乳房内新感染高风险期 Strategies to prevent new infections will include: 防止新感染策略包括 : Antibiotic dry cow therapy (DCT) 抗生素干奶牛治疗 (DCT) Internal or External Teat Sealants 内部或外部乳头密封剂 Dry-off strategies 干奶牛策略 Attention to housing, hygiene, and cow comfort 注意牛舍, 卫生和奶牛舒适 Good nutrition 良好营养 Vaccination (if available) 接种疫苗 ( 如果有 )
Summary 总结 Use dry cow antibiotic for cows with high SCC at dry off, or for all cows if high risk of new infection over the dry period 在干奶结束期对体细胞计位数高的牛使用干奶牛抗生素, 或者如果干奶期期间新发感染风险很高的话对所有奶牛用药 Use Orbeseal for cows with extended dry periods, if environmental conditions are poor, or if high risk of new infection over the dry period 如果环境条件差, 或者干奶期间新发感染风险很高的话, 对延长干奶期的牛使用 Orbeseal
Thank You 谢谢 Erin Royster, DVM, MS 艾琳 罗伊斯特博士 royster@umn.edu Veterinary Population Medicine University of Minnesota College of Veterinary Medicine